FORD EXPLORER HEATER PROBLEM

I HAVE A 1996 FORD EXPLORER I NOTICE MY MY WINDOWS, HEATER, AND BELL, GOES OFF WITHOUT THE KEY IN. I JUST HAD THE IGNITION REPLACED AND IT DID THIS BEFORE THAT. IF I TURN THE HEATER/ AC SWITCH ON THE BELL STOPS RINGING I AM THINKING IT IS THE FAN SWITCH CAN ANYONE OFFER SOME HELP? THANKS